The presence of lipids as major components of the aveolar surface-active material indicates their importance in lung function. The purpose of this research is to identify factors which regulate normal lipid metabolism in the lung. Isolated perfused rat lung will be uses to study the pathway of synthesis of lung lipids and the lipids of isolated surfactant material. The incorporation of fatty acids synthesized de novo in the lung as opposed to incorporation of exogenous fatty acids into lung phospholipids and specifically dipalmitoylphosphatidyl choline of the surfactantmaterial will be determined. The contribution of glucose and other related glycolytic and gluconeogenic intermediates as precursors of the fatty acids of dipalmitoylphosphatidyl choline and the pathway of their synthesis will be investigated as well as the imprtance and mechanism of the stimulation of glucose incorporation into lung phosphatidyl choline by increased CO2 concentration. As well, basic knowledge concerning the predominant pathways of carbohydrate metabolism and the dependence upon or control lipid synthesis by carbohydrate metabolism will be obtained. Study of the synthesis and storage of surfactant lipids In the isolated lamellar body fraction of lung tissue will determine the role of this subcellular component in surfactant production.